scribnee



2 Sheets-Sheet 1.

(No Model.)

0. E. SGRIBNER. SPRING JACK FOR TELEPHONE SWITGHBOABDS.

No. 596,626. Patented Jan. 4,1898.

745mm fifiar e' g 33 12222623 2% WWW By 6% Jfiazvz ey (No Model.) 2Sheets-$heet 2. 0. E. SORIBNER. SPRING JACK FOR TELEPHONE SWITUHBOARDS.

No. 596,626. Patented Jan.4,1898.

mix. :55 es Inflnior:

WWMM- YHE Noam; PETERS co nwound wssnmmmw u c.

NITED STATES PATENT rrrciE.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE IVESTERNELECTRIC COMPANY, OF SAME PLACE.

SPRING-JACK FOR TELEPHONE -SWITCHBOARDS.

SPECIFICATION forming part of Letters Patent No. 596,626, dated January4, 1898. Application filed May 14, 1896.' Serial No. 591,522. (Nomodel.)

To all whom it may concern.-

Be it known that I, CHARLES E. SCRIBNER, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvementin Spring-Jacks forTelephone- Switchboards, (Case No. 418,) of which the following is afull, clear, concise, and exact description, reference being had to theaccompanying drawings, forming a part of this specification.

My invention concerns the construction of spring-jack switches forswitchboards of tel.e-. phone-exchanges. It applies particularly tospring-jacks whose switch-springs and contact-straps are mountededgewise in grooves formed in a plate or base of insulating materialcarrying a number of spring-jacks.

The invention consists in certain details of construction of thespring-jack which may be enumerated, together with the particular objectof each, as follows: a bolt passing through the base-plate, having itsnut engaging one of the springs of the group constituting the contactsof a single spring-jack for the purpose of retaining the group ofsprings in the groove; the form of the said nut and the manner of itsengagement with the spring, whereby a reliable bearing upon the springis secured and whereby a simple and cheap process of manufacture ispermitted the countersinking of the head of said bolt in the insulatingbase-plate and the filling of the countersunk opening with a plug ofinsulating material for the purpose of maintaining a high insulation ofthe parts and of preventing access to the bolt after assemblage ofparts, and the provision on certain of the switch-springs ofdownwardly-proj ectin g lugs and apertures or recesses in theinsulatingbase to receive the said lugs, whereby when the springs are inplace their longitudinal or lateral movement is prevented.

The construction of the parts and the manner of assembling them in thespring-jack may be more readily described with reference to theaccompanying drawings.

In the drawings, Figure 1 is a plan of a strip of spring-jacks. Fig. 2is a front elevation of the strip, and Fig. 3 is a rear elevation of thesame. Fig. 4 is a view from beleft vacant.

place.

neath the strip. Fig. 5 is a perspective view of a group of springs andanvil-straps, to gether with two of the bolts, the parts being separatedto display their form, but disposed so as to represent their relation toeach other. Fig. 6 is a longitudinal section of the strip across one ofthe bolts on line 6 of Fig. 1. Fig. 7 is a longitudinal section of thestrip, showing the lugs on the anvil-straps and the recesses in whichthey lie, the section being taken on line 7 of Fig. 1. Fig. 8 is alongitudinal central section of a single spring-jack. Fig. 9 is anelevation of a plug which may be used with this spring-jack.

In forming the base or supporting plate a of insulating material toreceive the metallic parts transverse perforations a are bored into theedge of the strip at suitable intervals, and'grooves a are milled intothe upper face of the strip meeting these perforations to accommodatethe groups of springs constituting the jacks. These grooves aredisplayed in Fig. 1, where a few of the spaces have been The milledgroove (1 is narrowest at its rear portion. Throughout the greater partof its length it is made broader to permit free movement of the springs.The portion a of the grooveimmediately at the rear of the opening a ismade deeper also. In the floor of the groove and on its center line aperforation or recess a is formed. At each side of the narrow portionholes a a are drilled through the plate to permit the passage of thebolts for holding the springs in On the upper face of the strip acountersunk opening a is provided to receive each nut, of circular form,but with a lateral groove therefrom reaching to the groove a On theunder face of the strip the openings a a are countersunk at a a toreceive the heads of the bolts. From the lower portion of the transverseperforation a a hole 0. is drilled obliquely toward the under face ofthe strip, being met at its point of emergence by a transverse groove a,milled in the under surface of the strip.

The metallic contact portions of the springjack comprise a thimble b, apair of switchsprings c and d, and their respective contactanvils, withthe straps e and f carrying the anvils. The springs are of the formsshown ICO in Fig. 5. The spring 0 has a rearwardly-projecting extensionor lug to which a wire may be soldered. In its upper edge a small rectangular notch c is cut. The forward extremity of the spring is formedwith a downward curve in order that when the springs are laid in thegroove a the tip of the spring may lie in the same plane as the axis ofthe perforation a. The spring d is of similar form, but is shorter, inorder that its extremity may bear upon a different contact portion ofthe plug with which the spring-jack is adapted to be used; also thenotch d in its upper edge is in a difierent position to correspond withthe different position of the bolt at that side of the spring-jack. Bothsprings are perforated near their rear extremities with openings c and(1 respectively.

The anvil-straps e and f are alike in form. Each has a rearwardextension similar to that of thesprings, but differently disposed, inorder that the terminals of the spring-jack may not lie in the sameline. At the under edges of the springs e and f are formeddownwardly-projecting lugs e and f, respectively, in position to enterthe recess a in the baseplate. These straps also have openings 6 and fcorresponding in position to the openings c and d of the springs.

Tongues g, h, and 2', of rubber or other flexible insulating material,are provided for separating the springs. These tongues are of the samegeneral shape as the springs, but are shorter. They have perforations gh and i respectively, corresponding to the perforations in the springsand anvilstraps. One of the tongues h has a downwardly-projecting lug h,corresponding in position to the similar lugs on the anvil-straps.

The bolt for securing the springs in place comprises a screw 70,preferably with a broad slotted head, and a nut Z. This nut correspondsin diameter with the countersunk opening a and has a lateral projectionof a breadth equal to that of the lateral groove of the countersunkopening and is of such a length that when placed in the openingaforesaid it shall project into the groove C0 The contact-piece b is athimble adapted to fit the perforation a. It is provided with anextension formed to lie in the duct a and the groove a, leading to thatduct on the under surface of the strip.

In assembling this spring-jack the spring 0, tongue g, anvil-strap e,tongue h, anvilstrap f, tongue 2', and spring 01 are placed together inthe order named. Two tightly-fitting pins m, of hard rubber, are thenthrust through the openings 0 g e h f 2' 01 Whereby the parts are boundtogether. The bundle of springs and tongues is then forced into thegroove a the rear part fitting tightly into the narrowest portion ofthat groove. The lugs e and f of the anvil-straps, with the lug h of thetongue h between them, are then forced into the recess or opening or,which should be of such size as to fit them tightly.

Then the nuts Z are placed in the countersunk openings a their lateralextensions resting in the notches c and d of the springs c and 61,respectively. The screws 76 are screwed into these nuts from beneath,whereby the bundle of parts is drawn tightly into the groove ct. Whenthe bolts are in place, plugs n, of insulating material, are driven intothe countersunk openings a and a above the boltheads. Finally thethimble b is forced into the perforation a, the extension I) being ledthrough the duct and the groove, as has been already described, to therear of the springjack. The thimble may be held in place by a pinextending through a portion of the plate into it. When the parts arethus assembled, they are securely held in place and all unnecessary playof parts is prevented. The bundle of springs cannot move eithertransversely or longitudinally, the outer springs being held by thenuts, while the anvil-straps are held both bythe pins engaging the outersprings and the tongues entering the recess at. These tongues or lugsalso prevent any lateral motion of the anvils in response to the varyingpressure of their respective springs upon them during the insertion of aplug into the spring-jack. Further, the parts by means of which thecontact-springs are retained in place are inaccessible after thecompletion of the spring-jack, so that the springjack cannot be tamperedwith and injured by attempts to adjust or replace parts.

The spring-jack herein shown is adapted for use with the triple plugrepresented in Fig. 9. This plug has the usual three contactsurfaces 1),q, and T, which are adapted to register with the thimble b, the longerspring 0, and the shorter spring cl, respectively, of the spring-jack.Obviously, however, the details of construction which constitute thepresent invention may be applied to many other forms of springjackadapted for difierent plugs or having difierent dispositions ofcontact-surfaces.

I claim as my invention- 1. The combination with a switch-spring lyingon edge in a groove in a base-plate, of a bolt through the saidbase-plate having a nut of disk-like form with a lateral extension, saidnut lying in a countersunk opening of the base-plate, and said lateralextension being in engagement with arecess in the switchspring,substantiallyas described.

2. The combination, in a spring-jaok, of a base-plate of insulatingmaterial having a groove formed therein, a switch-spring and itsanvil-strap lying on edge in said groove, a lateral extension or lug onsaid anvil-strap, and a recess in the base-plate adapted to receive thesaid lug, whereby transverse movement of the anvil-strap is prevented.

3. In a spring-jack; the combination with a base-plate of insulatingmaterial having a groove milled therein, of a group of switchsprings andintermediate anvil-straps lying on edge in said groove,lateralextensions from the said anvil-straps near the eontact-anvils, and arecess adapted to receive the said extensions, substantially asdescribed.

4:. In aspring-jack, the combination with a base-plate of insulatingmaterial having a transverse groove formed therein, of a group ofline-springs and anvil-straps, with interposed tongues of insulatingmaterial, lying on edge in said groove, lateral extensions from I o theanvil-straps and from the tongue between

